| 摘要 |
<p>In the present invention, a laser beam with a prespecified oscillation frequency is divided into the arbitrary number of pulses to be irradiated to all holes in an area, and this step is repeated until the irradiation reaches a desired number of pulses, whereby an interactive time can be decided according to the number of divided pulses and a cooling period of time can be obtained, and also the number of pulses per one division is set to be a plurality of pulses, which allows an etching rate to be increased, so that the number of pulses required for machining can be reduced as compared to a case where a laser is irradiated to all the holes pulse by pulse.</p> |
